Combinations of Linear Units
Almost all tonal music can be understood as in terms of the four basic linear units discussed in this section and many figures that initially seem more complicated are often made up of a combination of one with another.

In this example, each note of an arpeggiation of a C major first inversion chord is decorated by a secondary linear unit - an incomplete neighbour note. Schenker called this a reaching over because the incomplete neighbour notes drop on to each note of of the arpeggiation from above - literally 'reaching over' the line sketched out by this primary linear unit.

Note the way that Schenkerian analyses are notated: there are no stems on the noteheads and a slur spans the linear unit or diminution in question. The stems and beams make the primary progression easier to see(see Notation Guide)

This example combines a descending third progression (marked with stems) with an ascending one (marked with a slur).

Here the secondary linear unit (the ascending progression) is prolonging a note that is conceptually a dissonant passing note (D against a C harmony).

In order for this passing note to be prolonged it must be made consonant as it is here by a dominant harmony . The ascending progression thus prolongs a new harmonic unit - G as V of C.

Schenker calls this a reaching under because the secondary progression approaches the passing note of the main progression from below (the German for reaching under is untergreifen but this is usually translated as 'motion from the inner voice').